[PATCH v2 06/21] platform: goldfish: pipe: Add DMA support to goldfish pipe

[PATCH v2 06/21] platform: goldfish: pipe: Add DMA support to goldfish pipe

[rkir]

From: Roman Kiryanov <rkir@google.com>

Goldfish DMA is an extension to the pipe device and is designed
to facilitate high-speed RAM->RAM transfers from guest to host.

See uapi/linux/goldfish/goldfish_dma.h for more details.

Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Lingfeng Yang <lfy@google.com>
---
Changes in v2:
 - Got sign-off from Lingfeng Yang.
 - Removed the license boilerplate from goldfish_dma.h.
 - Rebased.

 drivers/platform/goldfish/goldfish_pipe.c     | 312 +++++++++++++++++-
 .../platform/goldfish/goldfish_pipe_qemu.h    |   2 +
 include/uapi/linux/goldfish/goldfish_dma.h    |  71 ++++
 3 files changed, 383 insertions(+), 2 deletions(-)
 create mode 100644 include/uapi/linux/goldfish/goldfish_dma.h

diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index 56665e879e5a..7eb5436d7c35 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -63,21 +63,28 @@
 #include <linux/mm.h>
 #include <linux/acpi.h>
 #include <linux/bug.h>
+#include <uapi/linux/goldfish/goldfish_dma.h>
 #include "goldfish_pipe_qemu.h"
 
 /*
  * Update this when something changes in the driver's behavior so the host
  * can benefit from knowing it
+ * Notes:
+ *	version 2 was an intermediate release and isn't supported anymore.
+ *	version 3 is goldfish_pipe_v2 without DMA support.
+ *	version 4 (current) is goldfish_pipe_v2 with DMA support.
  */
 enum {
-	PIPE_DRIVER_VERSION = 2,
+	PIPE_DRIVER_VERSION = 4,
 	PIPE_CURRENT_DEVICE_VERSION = 2
 };
 
 enum {
 	MAX_BUFFERS_PER_COMMAND = 336,
 	MAX_SIGNALLED_PIPES = 64,
-	INITIAL_PIPES_CAPACITY = 64
+	INITIAL_PIPES_CAPACITY = 64,
+	DMA_REGION_MIN_SIZE = PAGE_SIZE,
+	DMA_REGION_MAX_SIZE = 256 << 20
 };
 
 struct goldfish_pipe_dev;
@@ -100,6 +107,11 @@ struct goldfish_pipe_command {
 			/* buffer sizes, guest -> host */
 			u32 sizes[MAX_BUFFERS_PER_COMMAND];
 		} rw_params;
+		/* Parameters for PIPE_CMD_DMA_HOST_(UN)MAP */
+		struct {
+			u64 dma_paddr;
+			u64 sz;
+		} dma_maphost_params;
 	};
 };
 
@@ -122,6 +134,24 @@ struct goldfish_pipe_dev_buffers {
 		signalled_pipe_buffers[MAX_SIGNALLED_PIPES];
 };
 
+/*
+ * The main data structure tracking state is
+ * struct goldfish_dma_context, which is included
+ * as an extra pointer field in struct goldfish_pipe.
+ * Each such context is associated with possibly
+ * one physical address and size describing the
+ * allocated DMA region, and only one allocation
+ * is allowed for each pipe fd. Further allocations
+ * require more open()'s of pipe fd's.
+ */
+struct goldfish_dma_context {
+	struct device *pdev_dev;	/* pointer to feed to dma_*_coherent */
+	void *dma_vaddr;		/* kernel vaddr of dma region */
+	size_t dma_size;		/* size of dma region */
+	dma_addr_t phys_begin;		/* paddr of dma region */
+	dma_addr_t phys_end;		/* paddr of dma region + dma_size */
+};
+
 /* This data type models a given pipe instance */
 struct goldfish_pipe {
 	/* pipe ID - index into goldfish_pipe_dev::pipes array */
@@ -162,6 +192,9 @@ struct goldfish_pipe {
 
 	/* A buffer of pages, too large to fit into a stack frame */
 	struct page *pages[MAX_BUFFERS_PER_COMMAND];
+
+	/* Holds information about reserved DMA region for this pipe */
+	struct goldfish_dma_context *dma;
 };
 
 /* The global driver data. Holds a reference to the i/o page used to
@@ -208,6 +241,9 @@ struct goldfish_pipe_dev {
 	int irq;
 	int version;
 	unsigned char __iomem *base;
+
+	/* DMA info */
+	size_t dma_alloc_total;
 };
 
 static struct goldfish_pipe_dev goldfish_pipe_dev;
@@ -739,6 +775,8 @@ static int goldfish_pipe_open(struct inode *inode, struct file *file)
 	spin_unlock_irqrestore(&dev->lock, flags);
 	if (status < 0)
 		goto err_cmd;
+	pipe->dma = NULL;
+
 	/* All is done, save the pipe into the file's private data field */
 	file->private_data = pipe;
 	return 0;
@@ -754,6 +792,40 @@ static int goldfish_pipe_open(struct inode *inode, struct file *file)
 	return status;
 }
 
+static void goldfish_pipe_dma_release_host(struct goldfish_pipe *pipe)
+{
+	struct goldfish_dma_context *dma = pipe->dma;
+	struct device *pdev_dev;
+
+	if (!dma)
+		return;
+
+	pdev_dev = pipe->dev->pdev_dev;
+
+	if (dma->dma_vaddr) {
+		pipe->command_buffer->dma_maphost_params.dma_paddr =
+			dma->phys_begin;
+		pipe->command_buffer->dma_maphost_params.sz = dma->dma_size;
+		goldfish_pipe_cmd(pipe, PIPE_CMD_DMA_HOST_UNMAP);
+	}
+}
+
+static void goldfish_pipe_dma_release_guest(struct goldfish_pipe *pipe)
+{
+	struct goldfish_dma_context *dma = pipe->dma;
+
+	if (!dma)
+		return;
+
+	if (dma->dma_vaddr) {
+		dma_free_coherent(dma->pdev_dev,
+				  dma->dma_size,
+				  dma->dma_vaddr,
+				  dma->phys_begin);
+		pipe->dev->dma_alloc_total -= dma->dma_size;
+	}
+}
+
 static int goldfish_pipe_release(struct inode *inode, struct file *filp)
 {
 	unsigned long flags;
@@ -761,6 +833,7 @@ static int goldfish_pipe_release(struct inode *inode, struct file *filp)
 	struct goldfish_pipe_dev *dev = pipe->dev;
 
 	/* The guest is closing the channel, so tell the emulator right now */
+	goldfish_pipe_dma_release_host(pipe);
 	goldfish_pipe_cmd(pipe, PIPE_CMD_CLOSE);
 
 	spin_lock_irqsave(&dev->lock, flags);
@@ -769,11 +842,242 @@ static int goldfish_pipe_release(struct inode *inode, struct file *filp)
 	spin_unlock_irqrestore(&dev->lock, flags);
 
 	filp->private_data = NULL;
+
+	/* Even if a fd is duped or involved in a forked process,
+	 * open/release methods are called only once, ever.
+	 * This makes goldfish_pipe_release a safe point
+	 * to delete the DMA region.
+	 */
+	goldfish_pipe_dma_release_guest(pipe);
+
+	kfree(pipe->dma);
 	free_page((unsigned long)pipe->command_buffer);
 	kfree(pipe);
+
 	return 0;
 }
 
+/* VMA open/close are for debugging purposes only.
+ * One might think that fork() (and thus pure calls to open())
+ * will require some sort of bookkeeping or refcounting
+ * for dma contexts (incl. when to call dma_free_coherent),
+ * but |vm_private_data| field and |vma_open/close| are only
+ * for situations where the driver needs to interact with vma's
+ * directly with its own per-VMA data structure (which does
+ * need to be refcounted).
+ *
+ * Here, we just use the kernel's existing
+ * VMA processing; we don't do anything on our own.
+ * The only reason we would want to do so is if we had to do
+ * special processing for the virtual (not physical) memory
+ * already associated with DMA memory; it is much less related
+ * to the task of knowing when to alloc/dealloc DMA memory.
+ */
+static void goldfish_dma_vma_open(struct vm_area_struct *vma)
+{
+	/* Not used */
+}
+
+static void goldfish_dma_vma_close(struct vm_area_struct *vma)
+{
+	/* Not used */
+}
+
+static const struct vm_operations_struct goldfish_dma_vm_ops = {
+	.open = goldfish_dma_vma_open,
+	.close = goldfish_dma_vma_close,
+};
+
+static bool is_page_size_multiple(unsigned long sz)
+{
+	return !(sz & (PAGE_SIZE - 1));
+}
+
+static bool check_region_size_valid(size_t size)
+{
+	if (size < DMA_REGION_MIN_SIZE)
+		return false;
+
+	if (size > DMA_REGION_MAX_SIZE)
+		return false;
+
+	return is_page_size_multiple(size);
+}
+
+static int goldfish_pipe_dma_alloc_locked(struct goldfish_pipe *pipe)
+{
+	struct goldfish_dma_context *dma = pipe->dma;
+
+	if (dma->dma_vaddr)
+		return 0;
+
+	dma->phys_begin = 0;
+	dma->dma_vaddr = dma_alloc_coherent(dma->pdev_dev,
+					    dma->dma_size,
+					    &dma->phys_begin,
+					    GFP_KERNEL);
+	if (!dma->dma_vaddr)
+		return -ENOMEM;
+	dma->phys_end = dma->phys_begin + dma->dma_size;
+	pipe->dev->dma_alloc_total += dma->dma_size;
+	pipe->command_buffer->dma_maphost_params.dma_paddr = dma->phys_begin;
+	pipe->command_buffer->dma_maphost_params.sz = dma->dma_size;
+	return goldfish_pipe_cmd_locked(pipe, PIPE_CMD_DMA_HOST_MAP);
+}
+
+static int goldfish_dma_mmap_locked(struct goldfish_pipe *pipe,
+				    struct vm_area_struct *vma)
+{
+	struct goldfish_dma_context *dma = pipe->dma;
+	struct device *pdev_dev = pipe->dev->pdev_dev;
+	size_t sz_requested = vma->vm_end - vma->vm_start;
+	int status;
+
+	if (!check_region_size_valid(sz_requested)) {
+		dev_err(pdev_dev, "%s: bad size (%zu) requested\n", __func__,
+			sz_requested);
+		return -EINVAL;
+	}
+
+	/* Alloc phys region if not allocated already. */
+	status = goldfish_pipe_dma_alloc_locked(pipe);
+	if (status)
+		return status;
+
+	status = remap_pfn_range(vma,
+				 vma->vm_start,
+				 dma->phys_begin >> PAGE_SHIFT,
+				 sz_requested,
+				 vma->vm_page_prot);
+	if (status < 0) {
+		dev_err(pdev_dev, "Cannot remap pfn range....\n");
+		return -EAGAIN;
+	}
+	vma->vm_ops = &goldfish_dma_vm_ops;
+	return 0;
+}
+
+/* When we call mmap() on a pipe fd, we obtain a pointer into
+ * the physically contiguous DMA region of the pipe device
+ * (Goldfish DMA).
+ */
+static int goldfish_dma_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct goldfish_pipe *pipe =
+		(struct goldfish_pipe *)(filp->private_data);
+	int status;
+
+	if (mutex_lock_interruptible(&pipe->lock))
+		return -ERESTARTSYS;
+
+	status = goldfish_dma_mmap_locked(pipe, vma);
+	mutex_unlock(&pipe->lock);
+	return status;
+}
+
+static int goldfish_pipe_dma_create_region(struct goldfish_pipe *pipe,
+					   size_t size)
+{
+	struct goldfish_dma_context *dma =
+		kzalloc(sizeof(struct goldfish_dma_context), GFP_KERNEL);
+	struct device *pdev_dev = pipe->dev->pdev_dev;
+
+	if (dma) {
+		if (mutex_lock_interruptible(&pipe->lock)) {
+			kfree(dma);
+			return -ERESTARTSYS;
+		}
+
+		if (pipe->dma) {
+			mutex_unlock(&pipe->lock);
+			kfree(dma);
+			dev_err(pdev_dev, "The DMA region already allocated\n");
+			return -EBUSY;
+		}
+
+		dma->dma_size = size;
+		dma->pdev_dev = pipe->dev->pdev_dev;
+		pipe->dma = dma;
+		mutex_unlock(&pipe->lock);
+		return 0;
+	}
+
+	dev_err(pdev_dev, "Could not allocate DMA context info!\n");
+	return -ENOMEM;
+}
+
+static long goldfish_dma_ioctl_getoff(struct goldfish_pipe *pipe,
+				      unsigned long arg)
+{
+	struct device *pdev_dev = pipe->dev->pdev_dev;
+	struct goldfish_dma_ioctl_info ioctl_data;
+	struct goldfish_dma_context *dma;
+
+	BUILD_BUG_ON(FIELD_SIZEOF(struct goldfish_dma_ioctl_info, phys_begin) <
+		FIELD_SIZEOF(struct goldfish_dma_context, phys_begin));
+
+	if (mutex_lock_interruptible(&pipe->lock)) {
+		dev_err(pdev_dev, "DMA_GETOFF: the pipe is not locked\n");
+		return -EACCES;
+	}
+
+	dma = pipe->dma;
+	if (dma) {
+		ioctl_data.phys_begin = dma->phys_begin;
+		ioctl_data.size = dma->dma_size;
+	} else {
+		ioctl_data.phys_begin = 0;
+		ioctl_data.size = 0;
+	}
+
+	if (copy_to_user((void __user *)arg, &ioctl_data,
+			 sizeof(ioctl_data))) {
+		mutex_unlock(&pipe->lock);
+		return -EFAULT;
+	}
+
+	mutex_unlock(&pipe->lock);
+	return 0;
+}
+
+static long goldfish_dma_ioctl_create_region(struct goldfish_pipe *pipe,
+					     unsigned long arg)
+{
+	struct goldfish_dma_ioctl_info ioctl_data;
+
+	if (copy_from_user(&ioctl_data, (void __user *)arg, sizeof(ioctl_data)))
+		return -EFAULT;
+
+	if (!check_region_size_valid(ioctl_data.size)) {
+		dev_err(pipe->dev->pdev_dev,
+			"DMA_CREATE_REGION: bad size (%lld) requested\n",
+			ioctl_data.size);
+		return -EINVAL;
+	}
+
+	return goldfish_pipe_dma_create_region(pipe, ioctl_data.size);
+}
+
+static long goldfish_dma_ioctl(struct file *file, unsigned int cmd,
+			       unsigned long arg)
+{
+	struct goldfish_pipe *pipe =
+		(struct goldfish_pipe *)(file->private_data);
+
+	switch (cmd) {
+	case GOLDFISH_DMA_IOC_LOCK:
+		return 0;
+	case GOLDFISH_DMA_IOC_UNLOCK:
+		wake_up_interruptible(&pipe->wake_queue);
+		return 0;
+	case GOLDFISH_DMA_IOC_GETOFF:
+		return goldfish_dma_ioctl_getoff(pipe, arg);
+	case GOLDFISH_DMA_IOC_CREATE_REGION:
+		return goldfish_dma_ioctl_create_region(pipe, arg);
+	}
+	return -ENOTTY;
+}
+
 static const struct file_operations goldfish_pipe_fops = {
 	.owner = THIS_MODULE,
 	.read = goldfish_pipe_read,
@@ -781,6 +1085,10 @@ static const struct file_operations goldfish_pipe_fops = {
 	.poll = goldfish_pipe_poll,
 	.open = goldfish_pipe_open,
 	.release = goldfish_pipe_release,
+	/* DMA-related operations */
+	.mmap = goldfish_dma_mmap,
+	.unlocked_ioctl = goldfish_dma_ioctl,
+	.compat_ioctl = goldfish_dma_ioctl,
 };
 
 static struct miscdevice goldfish_pipe_miscdev = {
diff --git a/drivers/platform/goldfish/goldfish_pipe_qemu.h b/drivers/platform/goldfish/goldfish_pipe_qemu.h
index b4d78c108afd..0ffc51dba54c 100644
--- a/drivers/platform/goldfish/goldfish_pipe_qemu.h
+++ b/drivers/platform/goldfish/goldfish_pipe_qemu.h
@@ -93,6 +93,8 @@ enum PipeCmdCode {
 	 * parallel processing of pipe operations on the host.
 	 */
 	PIPE_CMD_WAKE_ON_DONE_IO,
+	PIPE_CMD_DMA_HOST_MAP,
+	PIPE_CMD_DMA_HOST_UNMAP,
 };
 
 #endif /* GOLDFISH_PIPE_QEMU_H */
diff --git a/include/uapi/linux/goldfish/goldfish_dma.h b/include/uapi/linux/goldfish/goldfish_dma.h
new file mode 100644
index 000000000000..4f6fe0f2511a
--- /dev/null
+++ b/include/uapi/linux/goldfish/goldfish_dma.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#ifndef UAPI_GOLDFISH_DMA_H
+#define UAPI_GOLDFISH_DMA_H
+
+#include <linux/types.h>
+
+/* GOLDFISH DMA
+ *
+ * Goldfish DMA is an extension to the pipe device
+ * and is designed to facilitate high-speed RAM->RAM
+ * transfers from guest to host.
+ *
+ * Interface (guest side):
+ *
+ * The guest user calls goldfish_dma_alloc (ioctls)
+ * and then mmap() on a goldfish pipe fd,
+ * which means that it wants high-speed access to
+ * host-visible memory.
+ *
+ * The guest can then write into the pointer
+ * returned by mmap(), and these writes
+ * become immediately visible on the host without BQL
+ * or otherweise context switching.
+ *
+ * dma_alloc_coherent() is used to obtain contiguous
+ * physical memory regions, and we allocate and interact
+ * with this region on both guest and host through
+ * the following ioctls:
+ *
+ * - LOCK: lock the region for data access.
+ * - UNLOCK: unlock the region. This may also be done from the host
+ *   through the WAKE_ON_UNLOCK_DMA procedure.
+ * - CREATE_REGION: initialize size info for a dma region.
+ * - GETOFF: send physical address to guest drivers.
+ * - (UN)MAPHOST: uses goldfish_pipe_cmd to tell the host to
+ * (un)map to the guest physical address associated
+ * with the current dma context. This makes the physically
+ * contiguous memory (in)visible to the host.
+ *
+ * Guest userspace obtains a pointer to the DMA memory
+ * through mmap(), which also lazily allocates the memory
+ * with dma_alloc_coherent. (On last pipe close(), the region is freed).
+ * The mmaped() region can handle very high bandwidth
+ * transfers, and pipe operations can be used at the same
+ * time to handle synchronization and command communication.
+ */
+
+#define GOLDFISH_DMA_BUFFER_SIZE (32 * 1024 * 1024)
+
+struct goldfish_dma_ioctl_info {
+	__u64 phys_begin;
+	__u64 size;
+};
+
+/* There is an ioctl associated with goldfish dma driver.
+ * Make it conflict with ioctls that are not likely to be used
+ * in the emulator.
+ * 'G'	00-3F	drivers/misc/sgi-gru/grulib.h	conflict!
+ * 'G'	00-0F	linux/gigaset_dev.h	conflict!
+ */
+#define GOLDFISH_DMA_IOC_MAGIC	'G'
+#define GOLDFISH_DMA_IOC_OP(OP)	_IOWR(GOLDFISH_DMA_IOC_MAGIC, OP, \
+				struct goldfish_dma_ioctl_info)
+
+#define GOLDFISH_DMA_IOC_LOCK		GOLDFISH_DMA_IOC_OP(0)
+#define GOLDFISH_DMA_IOC_UNLOCK		GOLDFISH_DMA_IOC_OP(1)
+#define GOLDFISH_DMA_IOC_GETOFF		GOLDFISH_DMA_IOC_OP(2)
+#define GOLDFISH_DMA_IOC_CREATE_REGION	GOLDFISH_DMA_IOC_OP(3)
+
+#endif /* UAPI_GOLDFISH_DMA_H */
-- 
2.19.0.605.g01d371f741-goog

[PATCH v2 09/21] platform: goldfish: pipe: Remove the goldfish_pipe_dev global variable

[rkir]

From: Roman Kiryanov <rkir@google.com>

This is the last patch in the series of patches to remove mutable
global variables to introduce another version of the pipe driver
for the older host interface. I don't want to have two driver
states where only one is used.

Signed-off-by: Roman Kiryanov <rkir@google.com>
---
Changes in v2:
 - Rebased to address that goldfish_pipe_dev is static now.

 drivers/platform/goldfish/goldfish_pipe.c | 66 +++++++++++++----------
 1 file changed, 37 insertions(+), 29 deletions(-)

diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index b0cf4e59c0ec..c68035be4389 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -202,6 +202,9 @@ struct goldfish_pipe {
  * waiting to be awoken.
  */
 struct goldfish_pipe_dev {
+	/* A magic number to check if this is an instance of this struct */
+	void *magic;
+
 	/*
 	 * Global device spinlock. Protects the following members:
 	 *  - pipes, pipes_capacity
@@ -251,8 +254,6 @@ struct goldfish_pipe_dev {
 	size_t dma_alloc_total;
 };
 
-static struct goldfish_pipe_dev goldfish_pipe_dev;
-
 static int goldfish_pipe_cmd_locked(struct goldfish_pipe *pipe,
 				    enum PipeCmdCode cmd)
 {
@@ -647,6 +648,9 @@ static void goldfish_interrupt_task(unsigned long dev_addr)
 	}
 }
 
+static void goldfish_pipe_device_deinit(struct platform_device *pdev,
+					struct goldfish_pipe_dev *dev);
+
 /*
  * The general idea of the interrupt handling:
  *
@@ -667,7 +671,7 @@ static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id)
 	unsigned long flags;
 	struct goldfish_pipe_dev *dev = dev_id;
 
-	if (dev != &goldfish_pipe_dev)
+	if (dev->magic != &goldfish_pipe_device_deinit)
 		return IRQ_NONE;
 
 	/* Request the signalled pipes from the device */
@@ -719,6 +723,14 @@ static int get_free_pipe_id_locked(struct goldfish_pipe_dev *dev)
 	return id;
 }
 
+/* A helper function to get the instance of goldfish_pipe_dev from file */
+static struct goldfish_pipe_dev *to_goldfish_pipe_dev(struct file *file)
+{
+	struct miscdevice *miscdev = file->private_data;
+
+	return container_of(miscdev, struct goldfish_pipe_dev, miscdev);
+}
+
 /**
  *	goldfish_pipe_open - open a channel to the AVD
  *	@inode: inode of device
@@ -732,7 +744,7 @@ static int get_free_pipe_id_locked(struct goldfish_pipe_dev *dev)
  */
 static int goldfish_pipe_open(struct inode *inode, struct file *file)
 {
-	struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
+	struct goldfish_pipe_dev *dev = to_goldfish_pipe_dev(file);
 	unsigned long flags;
 	int id;
 	int status;
@@ -1112,9 +1124,9 @@ static void write_pa_addr(void *addr, void __iomem *portl, void __iomem *porth)
 	writel(lower_32_bits(paddr), portl);
 }
 
-static int goldfish_pipe_device_init(struct platform_device *pdev)
+static int goldfish_pipe_device_init(struct platform_device *pdev,
+				     struct goldfish_pipe_dev *dev)
 {
-	struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
 	int err;
 
 	tasklet_init(&dev->irq_tasklet, &goldfish_interrupt_task,
@@ -1169,26 +1181,29 @@ static int goldfish_pipe_device_init(struct platform_device *pdev)
 		      dev->base + PIPE_REG_OPEN_BUFFER,
 		      dev->base + PIPE_REG_OPEN_BUFFER_HIGH);
 
+	platform_set_drvdata(pdev, dev);
 	return 0;
 }
 
-static void goldfish_pipe_device_deinit(struct platform_device *pdev)
+static void goldfish_pipe_device_deinit(struct platform_device *pdev,
+					struct goldfish_pipe_dev *dev)
 {
-	misc_deregister(&goldfish_pipe_dev.miscdev);
-	tasklet_kill(&goldfish_pipe_dev.irq_tasklet);
-	kfree(goldfish_pipe_dev.pipes);
-	free_page((unsigned long)goldfish_pipe_dev.buffers);
+	misc_deregister(&dev->miscdev);
+	tasklet_kill(&dev->irq_tasklet);
+	kfree(dev->pipes);
+	free_page((unsigned long)dev->buffers);
 }
 
 static int goldfish_pipe_probe(struct platform_device *pdev)
 {
-	int err;
 	struct resource *r;
-	struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
+	struct goldfish_pipe_dev *dev;
 
-	/* not thread safe, but this should not happen */
-	WARN_ON(dev->base);
+	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
 
+	dev->magic = &goldfish_pipe_device_deinit;
 	spin_lock_init(&dev->lock);
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -1203,10 +1218,9 @@ static int goldfish_pipe_probe(struct platform_device *pdev)
 	}
 
 	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (!r) {
-		err = -EINVAL;
-		goto error;
-	}
+	if (!r)
+		return -EINVAL;
+
 	dev->irq = r->start;
 
 	/*
@@ -1221,20 +1235,14 @@ static int goldfish_pipe_probe(struct platform_device *pdev)
 	if (WARN_ON(dev->version < PIPE_CURRENT_DEVICE_VERSION))
 		return -EINVAL;
 
-	err = goldfish_pipe_device_init(pdev);
-	if (!err)
-		return 0;
-
-error:
-	dev->base = NULL;
-	return err;
+	return goldfish_pipe_device_init(pdev, dev);
 }
 
 static int goldfish_pipe_remove(struct platform_device *pdev)
 {
-	struct goldfish_pipe_dev *dev = &goldfish_pipe_dev;
-	goldfish_pipe_device_deinit(pdev);
-	dev->base = NULL;
+	struct goldfish_pipe_dev *dev = platform_get_drvdata(pdev);
+
+	goldfish_pipe_device_deinit(pdev, dev);
 	return 0;
 }
 
-- 
2.19.0.605.g01d371f741-goog

[PATCH v2 13/21] platform: goldfish: pipe: Split the driver to v2 specific and the rest

[rkir]

From: Roman Kiryanov <rkir@google.com>

Move probe/remove and other driver stuff to a separate file
to plug v1 there later.

Signed-off-by: Roman Kiryanov <rkir@google.com>
---
Changes in v2:
 - Removed breakage of allmodconfig.

 drivers/platform/goldfish/Makefile           |   3 +-
 drivers/platform/goldfish/goldfish_pipe.c    | 145 +++++++++++++++++++
 drivers/platform/goldfish/goldfish_pipe.h    |  24 +++
 drivers/platform/goldfish/goldfish_pipe_v2.c | 102 ++-----------
 drivers/platform/goldfish/goldfish_pipe_v2.h |  24 +++
 5 files changed, 210 insertions(+), 88 deletions(-)
 create mode 100644 drivers/platform/goldfish/goldfish_pipe.c
 create mode 100644 drivers/platform/goldfish/goldfish_pipe.h
 create mode 100644 drivers/platform/goldfish/goldfish_pipe_v2.h

diff --git a/drivers/platform/goldfish/Makefile b/drivers/platform/goldfish/Makefile
index 81f899a987a2..016769e003d8 100644
--- a/drivers/platform/goldfish/Makefile
+++ b/drivers/platform/goldfish/Makefile
@@ -1,4 +1,5 @@
 #
 # Makefile for Goldfish platform specific drivers
 #
-obj-$(CONFIG_GOLDFISH_PIPE)	+= goldfish_pipe_v2.o
+obj-$(CONFIG_GOLDFISH_PIPE)    += goldfish_pipe_all.o
+goldfish_pipe_all-objs := goldfish_pipe.o goldfish_pipe_v2.o
diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
new file mode 100644
index 000000000000..802bbf0d6d23
--- /dev/null
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2012 Intel, Inc.
+ * Copyright (C) 2013 Intel, Inc.
+ * Copyright (C) 2014 Linaro Limited
+ * Copyright (C) 2011-2016 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/* This source file contains the implementation of a special device driver
+ * that intends to provide a *very* fast communication channel between the
+ * guest system and the QEMU emulator.
+ *
+ * Usage from the guest is simply the following (error handling simplified):
+ *
+ *    int  fd = open("/dev/qemu_pipe",O_RDWR);
+ *    .... write() or read() through the pipe.
+ *
+ * This driver doesn't deal with the exact protocol used during the session.
+ * It is intended to be as simple as something like:
+ *
+ *    // do this _just_ after opening the fd to connect to a specific
+ *    // emulator service.
+ *    const char*  msg = "<pipename>";
+ *    if (write(fd, msg, strlen(msg)+1) < 0) {
+ *       ... could not connect to <pipename> service
+ *       close(fd);
+ *    }
+ *
+ *    // after this, simply read() and write() to communicate with the
+ *    // service. Exact protocol details left as an exercise to the reader.
+ *
+ * This driver is very fast because it doesn't copy any data through
+ * intermediate buffers, since the emulator is capable of translating
+ * guest user addresses into host ones.
+ *
+ * Note that we must however ensure that each user page involved in the
+ * exchange is properly mapped during a transfer.
+ */
+
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/acpi.h>
+#include "goldfish_pipe_qemu.h"
+#include "goldfish_pipe.h"
+#include "goldfish_pipe_v2.h"
+
+/*
+ * Update this when something changes in the driver's behavior so the host
+ * can benefit from knowing it
+ * Notes:
+ *	version 2 was an intermediate release and isn't supported anymore.
+ *	version 3 is goldfish_pipe_v2 without DMA support.
+ *	version 4 (current) is goldfish_pipe_v2 with DMA support.
+ */
+enum {
+	PIPE_DRIVER_VERSION = 4,
+	PIPE_CURRENT_DEVICE_VERSION = 2
+};
+
+static int goldfish_pipe_probe(struct platform_device *pdev)
+{
+	struct resource *r;
+	char __iomem *base;
+	int irq;
+	int version;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r || resource_size(r) < PAGE_SIZE) {
+		dev_err(&pdev->dev, "can't allocate i/o page\n");
+		return -EINVAL;
+	}
+	base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
+	if (!base) {
+		dev_err(&pdev->dev, "ioremap failed\n");
+		return -EINVAL;
+	}
+
+	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!r)
+		return -EINVAL;
+
+	irq = r->start;
+
+	/*
+	 * Exchange the versions with the host device
+	 *
+	 * Note: v1 driver used to not report its version, so we write it before
+	 *  reading device version back: this allows the host implementation to
+	 *  detect the old driver (if there was no version write before read).
+	 */
+	writel((u32)PIPE_DRIVER_VERSION, base + PIPE_REG_VERSION);
+	version = readl(base + PIPE_REG_VERSION);
+
+	if (WARN_ON(version < PIPE_CURRENT_DEVICE_VERSION))
+		return -EINVAL;
+
+	return goldfish_pipe_device_init(pdev, base, irq);
+}
+
+static int goldfish_pipe_remove(struct platform_device *pdev)
+{
+	struct goldfish_pipe_dev_base *dev = platform_get_drvdata(pdev);
+
+	return dev->deinit(dev, pdev);
+}
+
+static const struct acpi_device_id goldfish_pipe_acpi_match[] = {
+	{ "GFSH0003", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, goldfish_pipe_acpi_match);
+
+static const struct of_device_id goldfish_pipe_of_match[] = {
+	{ .compatible = "google,android-pipe", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, goldfish_pipe_of_match);
+
+static struct platform_driver goldfish_pipe_driver = {
+	.probe = goldfish_pipe_probe,
+	.remove = goldfish_pipe_remove,
+	.driver = {
+		.name = "goldfish_pipe",
+		.of_match_table = goldfish_pipe_of_match,
+		.acpi_match_table = ACPI_PTR(goldfish_pipe_acpi_match),
+	}
+};
+
+module_platform_driver(goldfish_pipe_driver);
+MODULE_AUTHOR("David Turner <digit@google.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/platform/goldfish/goldfish_pipe.h b/drivers/platform/goldfish/goldfish_pipe.h
new file mode 100644
index 000000000000..41e831f59eff
--- /dev/null
+++ b/drivers/platform/goldfish/goldfish_pipe.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2018 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef GOLDFISH_PIPE_H
+#define GOLDFISH_PIPE_H
+
+struct goldfish_pipe_dev_base {
+	/* the destructor, the pointer is set in init */
+	int (*deinit)(void *pipe_dev, struct platform_device *pdev);
+};
+
+#endif /* GOLDFISH_PIPE_H */
diff --git a/drivers/platform/goldfish/goldfish_pipe_v2.c b/drivers/platform/goldfish/goldfish_pipe_v2.c
index 7187b2e603d4..d653e5a2ffcc 100644
--- a/drivers/platform/goldfish/goldfish_pipe_v2.c
+++ b/drivers/platform/goldfish/goldfish_pipe_v2.c
@@ -47,8 +47,6 @@
  * exchange is properly mapped during a transfer.
  */
 
-#include <linux/module.h>
-#include <linux/mod_devicetable.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/spinlock.h>
@@ -61,10 +59,10 @@
 #include <linux/io.h>
 #include <linux/dma-mapping.h>
 #include <linux/mm.h>
-#include <linux/acpi.h>
 #include <linux/bug.h>
 #include <uapi/linux/goldfish/goldfish_dma.h>
 #include "goldfish_pipe_qemu.h"
+#include "goldfish_pipe.h"
 
 /*
  * Update this when something changes in the driver's behavior so the host
@@ -89,6 +87,9 @@ enum {
 
 struct goldfish_pipe_dev;
 
+static int goldfish_pipe_device_deinit(void *raw_dev,
+				       struct platform_device *pdev);
+
 /* A per-pipe command structure, shared with the host */
 struct goldfish_pipe_command {
 	s32 cmd;	/* PipeCmdCode, guest -> host */
@@ -202,8 +203,8 @@ struct goldfish_pipe {
  * waiting to be awoken.
  */
 struct goldfish_pipe_dev {
-	/* A magic number to check if this is an instance of this struct */
-	void *magic;
+	/* Needed for 'remove' */
+	struct goldfish_pipe_dev_base super;
 
 	/*
 	 * Global device spinlock. Protects the following members:
@@ -646,9 +647,6 @@ static void goldfish_interrupt_task(unsigned long dev_addr)
 	}
 }
 
-static void goldfish_pipe_device_deinit(struct platform_device *pdev,
-					struct goldfish_pipe_dev *dev);
-
 /*
  * The general idea of the interrupt handling:
  *
@@ -669,7 +667,7 @@ static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id)
 	unsigned long flags;
 	struct goldfish_pipe_dev *dev = dev_id;
 
-	if (dev->magic != &goldfish_pipe_device_deinit)
+	if (dev->super.deinit != &goldfish_pipe_device_deinit)
 		return IRQ_NONE;
 
 	/* Request the signalled pipes from the device */
@@ -1122,9 +1120,9 @@ static void write_pa_addr(void *addr, void __iomem *portl, void __iomem *porth)
 	writel(lower_32_bits(paddr), portl);
 }
 
-static int goldfish_pipe_device_init(struct platform_device *pdev,
-				     char __iomem *base,
-				     int irq)
+int goldfish_pipe_device_init(struct platform_device *pdev,
+			      char __iomem *base,
+			      int irq)
 {
 	struct goldfish_pipe_dev *dev;
 	int err;
@@ -1133,7 +1131,7 @@ static int goldfish_pipe_device_init(struct platform_device *pdev,
 	if (!dev)
 		return -ENOMEM;
 
-	dev->magic = &goldfish_pipe_device_deinit;
+	dev->super.deinit = &goldfish_pipe_device_deinit;
 	spin_lock_init(&dev->lock);
 
 	tasklet_init(&dev->irq_tasklet, &goldfish_interrupt_task,
@@ -1193,9 +1191,11 @@ static int goldfish_pipe_device_init(struct platform_device *pdev,
 	return 0;
 }
 
-static int goldfish_pipe_device_deinit(struct platform_device *pdev,
-				       struct goldfish_pipe_dev *dev)
+static int goldfish_pipe_device_deinit(void *raw_dev,
+				       struct platform_device *pdev)
 {
+	struct goldfish_pipe_dev *dev = raw_dev;
+
 	misc_deregister(&dev->miscdev);
 	tasklet_kill(&dev->irq_tasklet);
 	kfree(dev->pipes);
@@ -1203,75 +1203,3 @@ static int goldfish_pipe_device_deinit(struct platform_device *pdev,
 
 	return 0;
 }
-
-static int goldfish_pipe_probe(struct platform_device *pdev)
-{
-	struct resource *r;
-	char __iomem *base;
-	int irq;
-	int version;
-
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!r || resource_size(r) < PAGE_SIZE) {
-		dev_err(&pdev->dev, "can't allocate i/o page\n");
-		return -EINVAL;
-	}
-	base = devm_ioremap(&pdev->dev, r->start, PAGE_SIZE);
-	if (!base) {
-		dev_err(&pdev->dev, "ioremap failed\n");
-		return -EINVAL;
-	}
-
-	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (!r)
-		return -EINVAL;
-
-	irq = r->start;
-
-	/*
-	 * Exchange the versions with the host device
-	 *
-	 * Note: v1 driver used to not report its version, so we write it before
-	 *  reading device version back: this allows the host implementation to
-	 *  detect the old driver (if there was no version write before read).
-	 */
-	writel((u32)PIPE_DRIVER_VERSION, base + PIPE_REG_VERSION);
-	version = readl(base + PIPE_REG_VERSION);
-	if (WARN_ON(version < PIPE_CURRENT_DEVICE_VERSION))
-		return -EINVAL;
-
-	return goldfish_pipe_device_init(pdev, base, irq);
-}
-
-static int goldfish_pipe_remove(struct platform_device *pdev)
-{
-	struct goldfish_pipe_dev *dev = platform_get_drvdata(pdev);
-
-	return goldfish_pipe_device_deinit(pdev, dev);
-}
-
-static const struct acpi_device_id goldfish_pipe_acpi_match[] = {
-	{ "GFSH0003", 0 },
-	{ },
-};
-MODULE_DEVICE_TABLE(acpi, goldfish_pipe_acpi_match);
-
-static const struct of_device_id goldfish_pipe_of_match[] = {
-	{ .compatible = "google,android-pipe", },
-	{},
-};
-MODULE_DEVICE_TABLE(of, goldfish_pipe_of_match);
-
-static struct platform_driver goldfish_pipe_driver = {
-	.probe = goldfish_pipe_probe,
-	.remove = goldfish_pipe_remove,
-	.driver = {
-		.name = "goldfish_pipe",
-		.of_match_table = goldfish_pipe_of_match,
-		.acpi_match_table = ACPI_PTR(goldfish_pipe_acpi_match),
-	}
-};
-
-module_platform_driver(goldfish_pipe_driver);
-MODULE_AUTHOR("David Turner <digit@google.com>");
-MODULE_LICENSE("GPL v2");
diff --git a/drivers/platform/goldfish/goldfish_pipe_v2.h b/drivers/platform/goldfish/goldfish_pipe_v2.h
new file mode 100644
index 000000000000..679d863774a8
--- /dev/null
+++ b/drivers/platform/goldfish/goldfish_pipe_v2.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2018 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef GOLDFISH_PIPE_V2_H
+#define GOLDFISH_PIPE_V2_H
+
+/* The entry point to the pipe v2 driver */
+int goldfish_pipe_device_init(struct platform_device *pdev,
+			      char __iomem *base,
+			      int irq);
+
+#endif /* #define GOLDFISH_PIPE_V2_H */
-- 
2.19.0.605.g01d371f741-goog

[PATCH v2 19/21] platform: goldfish: pipe: Add the goldfish_pipe_v1 driver

[rkir]

From: Roman Kiryanov <rkir@google.com>

This is the v1 goldfish pipe driver.

Signed-off-by: Roman Kiryanov <rkir@google.com>
---
Changes in v2:
 - Rebased (Makefile).

 drivers/platform/goldfish/Makefile            |   2 +-
 drivers/platform/goldfish/goldfish_pipe.c     |   9 +-
 .../platform/goldfish/goldfish_pipe_qemu.h    |  27 +
 drivers/platform/goldfish/goldfish_pipe_v1.c  | 632 ++++++++++++++++++
 drivers/platform/goldfish/goldfish_pipe_v1.h  |  24 +
 5 files changed, 689 insertions(+), 5 deletions(-)
 create mode 100644 drivers/platform/goldfish/goldfish_pipe_v1.c
 create mode 100644 drivers/platform/goldfish/goldfish_pipe_v1.h

diff --git a/drivers/platform/goldfish/Makefile b/drivers/platform/goldfish/Makefile
index 016769e003d8..3fb7427b9dd8 100644
--- a/drivers/platform/goldfish/Makefile
+++ b/drivers/platform/goldfish/Makefile
@@ -2,4 +2,4 @@
 # Makefile for Goldfish platform specific drivers
 #
 obj-$(CONFIG_GOLDFISH_PIPE)    += goldfish_pipe_all.o
-goldfish_pipe_all-objs := goldfish_pipe.o goldfish_pipe_v2.o
+goldfish_pipe_all-objs := goldfish_pipe.o goldfish_pipe_v1.o goldfish_pipe_v2.o
diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index d963b7485ce5..e45e262517a0 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -56,6 +56,7 @@
 #include <linux/acpi.h>
 #include "goldfish_pipe_qemu.h"
 #include "goldfish_pipe.h"
+#include "goldfish_pipe_v1.h"
 #include "goldfish_pipe_v2.h"
 
 /*
@@ -105,10 +106,10 @@ static int goldfish_pipe_probe(struct platform_device *pdev)
 	writel((u32)PIPE_DRIVER_VERSION, base + PIPE_V2_REG_VERSION);
 	version = readl(base + PIPE_V2_REG_VERSION);
 
-	if (WARN_ON(version < PIPE_CURRENT_DEVICE_VERSION))
-		return -EINVAL;
-
-	return goldfish_pipe_device_v2_init(pdev, base, irq);
+	if (version < PIPE_CURRENT_DEVICE_VERSION)
+		return goldfish_pipe_device_v1_init(pdev, base, irq);
+	else
+		return goldfish_pipe_device_v2_init(pdev, base, irq);
 }
 
 static int goldfish_pipe_remove(struct platform_device *pdev)
diff --git a/drivers/platform/goldfish/goldfish_pipe_qemu.h b/drivers/platform/goldfish/goldfish_pipe_qemu.h
index 599b69f0baa1..ed2c7938fede 100644
--- a/drivers/platform/goldfish/goldfish_pipe_qemu.h
+++ b/drivers/platform/goldfish/goldfish_pipe_qemu.h
@@ -62,6 +62,33 @@ enum PipeFlagsBits {
 	BIT_WAKE_ON_READ   = 2,  /* want to be woken on reads */
 };
 
+enum PipeV1Regs {
+	/* write: value = command */
+	PIPE_V1_REG_COMMAND		= 0x00,
+	/* read */
+	PIPE_V1_REG_STATUS		= 0x04,
+	/* read/write: channel id */
+	PIPE_V1_REG_CHANNEL		= 0x08,
+	/* read/write: channel id */
+	PIPE_V1_REG_CHANNEL_HIGH	= 0x30,
+	/* read/write: buffer size */
+	PIPE_V1_REG_SIZE		= 0x0C,
+	/* write: physical address */
+	PIPE_V1_REG_ADDRESS		= 0x10,
+	/* write: physical address */
+	PIPE_V1_REG_ADDRESS_HIGH	= 0x34,
+	/* read: wake flags */
+	PIPE_V1_REG_WAKES		= 0x14,
+	/* read/write: batch data address */
+	PIPE_V1_REG_PARAMS_ADDR_LOW	= 0x18,
+	/* read/write: batch data address */
+	PIPE_V1_REG_PARAMS_ADDR_HIGH	= 0x1C,
+	/* write: batch access */
+	PIPE_V1_REG_ACCESS_PARAMS	= 0x20,
+	/* read: device version */
+	PIPE_V1_REG_VERSION		= 0x24,
+};
+
 enum PipeV2Regs {
 	PIPE_V2_REG_CMD = 0,
 
diff --git a/drivers/platform/goldfish/goldfish_pipe_v1.c b/drivers/platform/goldfish/goldfish_pipe_v1.c
new file mode 100644
index 000000000000..6e603204dd62
--- /dev/null
+++ b/drivers/platform/goldfish/goldfish_pipe_v1.c
@@ -0,0 +1,632 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2011 Google, Inc.
+ * Copyright (C) 2012 Intel, Inc.
+ * Copyright (C) 2013 Intel, Inc.
+ * Copyright (C) 2014 Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/* This source file contains the implementation of the legacy version of
+ * a goldfish pipe device driver. See goldfish_pipe_v2.c for the current
+ * version.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+#include <linux/mm.h>
+#include <linux/bug.h>
+#include <linux/goldfish.h>
+#include "goldfish_pipe_qemu.h"
+#include "goldfish_pipe.h"
+
+#define MAX_PAGES_TO_GRAB 32
+
+/* A value that will not be set by qemu emulator */
+#define INITIAL_BATCH_RESULT (0xdeadbeaf)
+
+struct goldfish_pipe_dev;
+
+/* This data type models a given pipe instance */
+struct goldfish_pipe {
+	struct goldfish_pipe_dev *dev;
+
+	/* The wake flags pipe is waiting for
+	 * Note: not protected with any lock, uses atomic operations
+	 *  and barriers to make it thread-safe.
+	 */
+	unsigned long flags;
+
+	wait_queue_head_t wake_queue;
+
+	/* protects access to the pipe */
+	struct mutex lock;
+};
+
+struct access_params {
+	unsigned long channel;
+	u32 size;
+	unsigned long address;
+	u32 cmd;
+	u32 result;
+	/* reserved for future extension */
+	u32 flags;
+};
+
+/* The driver state. Holds a reference to the i/o page used to
+ * communicate with the emulator, and a wake queue for blocked tasks
+ * waiting to be awoken.
+ */
+struct goldfish_pipe_dev {
+	/* Needed for the 'remove' call */
+	struct goldfish_pipe_dev_base super;
+
+	/* ptr to platform device's device struct */
+	struct device *pdev_dev;
+
+	/* the base address for MMIO */
+	char __iomem *base;
+
+	struct access_params *aps;
+
+	struct miscdevice miscdev;
+
+	/* Global device spinlock */
+	spinlock_t lock;
+};
+
+static int goldfish_pipe_device_deinit(void *raw_dev,
+				       struct platform_device *pdev);
+
+static u32 goldfish_cmd_status(struct goldfish_pipe *pipe, u32 cmd)
+{
+	unsigned long flags;
+	u32 status;
+	struct goldfish_pipe_dev *dev = pipe->dev;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	gf_write_ptr(pipe, dev->base + PIPE_V1_REG_CHANNEL,
+		     dev->base + PIPE_V1_REG_CHANNEL_HIGH);
+	writel(cmd, dev->base + PIPE_V1_REG_COMMAND);
+	status = readl(dev->base + PIPE_V1_REG_STATUS);
+	spin_unlock_irqrestore(&dev->lock, flags);
+	return status;
+}
+
+static void goldfish_cmd(struct goldfish_pipe *pipe, u32 cmd)
+{
+	unsigned long flags;
+	struct goldfish_pipe_dev *dev = pipe->dev;
+
+	spin_lock_irqsave(&dev->lock, flags);
+	gf_write_ptr(pipe, dev->base + PIPE_V1_REG_CHANNEL,
+		     dev->base + PIPE_V1_REG_CHANNEL_HIGH);
+	writel(cmd, dev->base + PIPE_V1_REG_COMMAND);
+	spin_unlock_irqrestore(&dev->lock, flags);
+}
+
+/* This function converts an error code returned by the emulator through
+ * the PIPE_V1_REG_STATUS i/o register into a valid negative errno value.
+ */
+static int goldfish_pipe_error_convert(int status)
+{
+	switch (status) {
+	case PIPE_ERROR_AGAIN:
+		return -EAGAIN;
+	case PIPE_ERROR_NOMEM:
+		return -ENOMEM;
+	case PIPE_ERROR_IO:
+		return -EIO;
+	default:
+		return -EINVAL;
+	}
+}
+
+/*
+ * Notice: QEMU will return 0 for un-known register access, indicating
+ * access_params is supported or not
+ */
+static int valid_batchbuffer_addr(struct goldfish_pipe_dev *dev,
+				  struct access_params *aps)
+{
+	u32 aph, apl;
+	u64 paddr;
+
+	aph = readl(dev->base + PIPE_V1_REG_PARAMS_ADDR_HIGH);
+	apl = readl(dev->base + PIPE_V1_REG_PARAMS_ADDR_LOW);
+
+	paddr = ((u64)aph << 32) | apl;
+	return paddr == (__pa(aps));
+}
+
+static int setup_access_params_addr(struct platform_device *pdev,
+				    struct goldfish_pipe_dev *dev)
+{
+	u64 paddr;
+	struct access_params *aps;
+
+	aps = devm_kzalloc(&pdev->dev, sizeof(struct access_params),
+			   GFP_KERNEL);
+	if (!aps)
+		return -ENOMEM;
+
+	paddr = __pa(aps);
+	writel((u32)(paddr >> 32), dev->base + PIPE_V1_REG_PARAMS_ADDR_HIGH);
+	writel((u32)paddr, dev->base + PIPE_V1_REG_PARAMS_ADDR_LOW);
+
+	if (valid_batchbuffer_addr(dev, aps)) {
+		dev->aps = aps;
+		return 0;
+	}
+
+	devm_kfree(&pdev->dev, aps);
+	return -EFAULT;
+}
+
+static int access_with_param(struct goldfish_pipe_dev *dev, const int cmd,
+			     unsigned long address, unsigned long avail,
+			     struct goldfish_pipe *pipe, int *status)
+{
+	struct access_params *aps = dev->aps;
+
+	if (!aps)
+		return -EINVAL;
+
+	aps->result = INITIAL_BATCH_RESULT;
+	aps->channel = (unsigned long)pipe;
+	aps->size = avail;
+	aps->address = address;
+	aps->cmd = cmd;
+	writel(cmd, dev->base + PIPE_V1_REG_ACCESS_PARAMS);
+
+	/*
+	 * If the aps->result has not changed, that means
+	 * that the batch command failed
+	 */
+	if (aps->result == INITIAL_BATCH_RESULT)
+		return -EINVAL;
+
+	*status = aps->result;
+	return 0;
+}
+
+static int transfer_pages(struct goldfish_pipe_dev *dev,
+			  struct goldfish_pipe *pipe,
+			  int cmd,
+			  unsigned long xaddr,
+			  unsigned long size)
+{
+	unsigned long irq_flags;
+	int status = 0;
+
+	spin_lock_irqsave(&dev->lock, irq_flags);
+	if (access_with_param(dev, cmd, xaddr, size, pipe, &status)) {
+		gf_write_ptr(pipe, dev->base + PIPE_V1_REG_CHANNEL,
+			     dev->base + PIPE_V1_REG_CHANNEL_HIGH);
+
+		writel(size, dev->base + PIPE_V1_REG_SIZE);
+
+		gf_write_ptr((void *)xaddr,
+			     dev->base + PIPE_V1_REG_ADDRESS,
+			     dev->base + PIPE_V1_REG_ADDRESS_HIGH);
+
+		writel(cmd, dev->base + PIPE_V1_REG_COMMAND);
+
+		status = readl(dev->base + PIPE_V1_REG_STATUS);
+	}
+	spin_unlock_irqrestore(&dev->lock, irq_flags);
+
+	return status;
+}
+
+static unsigned long translate_address(const struct page *page,
+				       unsigned long addr)
+{
+	return page_to_phys(page) | (addr & ~PAGE_MASK);
+}
+
+static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
+					size_t bufflen, int is_write)
+{
+	struct goldfish_pipe *pipe = filp->private_data;
+	struct goldfish_pipe_dev *dev = pipe->dev;
+	unsigned long address;
+	unsigned long address_end;
+	const int wake_bit = is_write ? BIT_WAKE_ON_WRITE : BIT_WAKE_ON_READ;
+	const int pipe_cmd = is_write ? PIPE_CMD_WRITE : PIPE_CMD_READ;
+	int count = 0;
+	int ret = -EINVAL;
+
+	/* If the emulator already closed the pipe, no need to go further */
+	if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+		return -EIO;
+
+	/* Null reads or writes succeeds */
+	if (unlikely(bufflen == 0))
+		return 0;
+
+	/* Check the buffer range for access */
+	if (!access_ok(is_write ? VERIFY_WRITE : VERIFY_READ,
+		       buffer, bufflen))
+		return -EFAULT;
+
+	address = (unsigned long)buffer;
+	address_end = address + bufflen;
+
+	/* Serialize access to the pipe */
+	if (mutex_lock_interruptible(&pipe->lock))
+		return -ERESTARTSYS;
+
+	while (address < address_end) {
+		struct page *pages[MAX_PAGES_TO_GRAB];
+		unsigned long page_end = (address & PAGE_MASK) + PAGE_SIZE;
+		unsigned long avail;
+		unsigned long xaddr;
+		unsigned long xaddr_prev;
+		long first_page;
+		long last_page;
+		long requested_pages;
+		int status;
+		int n_pages;
+		int page_i;
+		int num_contiguous_pages;
+
+		/*
+		 * Attempt to grab multiple physically contiguous pages.
+		 */
+		first_page = address & PAGE_MASK;
+		last_page = (address_end - 1) & PAGE_MASK;
+		requested_pages =
+			min(((last_page - first_page) >> PAGE_SHIFT) + 1,
+			    (long)MAX_PAGES_TO_GRAB);
+
+		ret = get_user_pages_fast(first_page, requested_pages,
+					  !is_write, pages);
+		if (ret < 0) {
+			dev_err(dev->pdev_dev,
+				"%s: get_user_pages_fast failed: %d\n",
+				__func__, ret);
+			break;
+		} else if (!ret) {
+			dev_err(dev->pdev_dev,
+				"%s: error: no pages returned, requested %ld\n",
+				__func__, requested_pages);
+			break;
+		}
+
+		n_pages = ret;
+		xaddr = translate_address(pages[0], address);
+		xaddr_prev = xaddr;
+		num_contiguous_pages = 1;
+		for (page_i = 1; page_i < n_pages; page_i++) {
+			unsigned long xaddr_i;
+
+			xaddr_i = translate_address(pages[page_i], address);
+			if (xaddr_i == xaddr_prev + PAGE_SIZE) {
+				page_end += PAGE_SIZE;
+				xaddr_prev = xaddr_i;
+				num_contiguous_pages++;
+			} else {
+				dev_err(dev->pdev_dev,
+					"%s: discontinuous page boundary: %d "
+					"pages instead\n",
+					__func__, page_i);
+				break;
+			}
+		}
+		avail = min(page_end, address_end) - address;
+
+		status = transfer_pages(dev, pipe, pipe_cmd, xaddr, avail);
+
+		for (page_i = 0; page_i < n_pages; page_i++) {
+			if (status > 0 && !is_write &&
+			    page_i < num_contiguous_pages)
+				set_page_dirty(pages[page_i]);
+
+			put_page(pages[page_i]);
+		}
+
+		if (status > 0) { /* Correct transfer */
+			count += status;
+			address += status;
+			continue;
+		} else if (status == 0) { /* EOF */
+			ret = 0;
+			break;
+		} else if (status < 0 && count > 0) {
+			/*
+			 * An error occurred and we already transferred
+			 * something on one of the previous pages.
+			 * Just return what we already copied and log this
+			 * err.
+			 *
+			 * Note: This seems like an incorrect approach but
+			 * cannot change it until we check if any user space
+			 * ABI relies on this behavior.
+			 */
+			if (status != PIPE_ERROR_AGAIN)
+				dev_err_ratelimited(dev->pdev_dev,
+					"backend returned error %d on %s\n",
+					status, is_write ? "write" : "read");
+			ret = 0;
+			break;
+		}
+
+		/*
+		 * If the error is not PIPE_ERROR_AGAIN, or if we are not in
+		 * non-blocking mode, just return the error code.
+		 */
+		if (status != PIPE_ERROR_AGAIN ||
+		    (filp->f_flags & O_NONBLOCK) != 0) {
+			ret = goldfish_pipe_error_convert(status);
+			break;
+		}
+
+		/*
+		 * The backend blocked the read/write, wait until the backend
+		 * tells us it's ready to process more data.
+		 */
+		set_bit(wake_bit, &pipe->flags);
+
+		/* Tell the emulator we're going to wait for a wake event */
+		goldfish_cmd(pipe, pipe_cmd);
+
+		/* Unlock the pipe, then wait for the wake signal */
+		mutex_unlock(&pipe->lock);
+
+		while (test_bit(wake_bit, &pipe->flags)) {
+			if (wait_event_interruptible(pipe->wake_queue,
+					!test_bit(wake_bit, &pipe->flags)))
+				return -ERESTARTSYS;
+
+			if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+				return -EIO;
+		}
+
+		/* Try to re-acquire the lock */
+		if (mutex_lock_interruptible(&pipe->lock))
+			return -ERESTARTSYS;
+	}
+	mutex_unlock(&pipe->lock);
+
+	return (ret < 0) ? ret : count;
+}
+
+static ssize_t goldfish_pipe_read(struct file *filp, char __user *buffer,
+				  size_t bufflen, loff_t *ppos)
+{
+	return goldfish_pipe_read_write(filp, buffer, bufflen,
+					/* is_write */ 0);
+}
+
+static ssize_t goldfish_pipe_write(struct file *filp,
+				   const char __user *buffer, size_t bufflen,
+				   loff_t *ppos)
+{
+	return goldfish_pipe_read_write(filp, (char __user *)buffer,
+					bufflen, /* is_write */ 1);
+}
+
+static __poll_t goldfish_pipe_poll(struct file *filp, poll_table *wait)
+{
+	struct goldfish_pipe *pipe = filp->private_data;
+	__poll_t mask = 0;
+	int status;
+
+	if (mutex_lock_interruptible(&pipe->lock))
+		return -ERESTARTSYS;
+
+	poll_wait(filp, &pipe->wake_queue, wait);
+
+	status = goldfish_cmd_status(pipe, PIPE_CMD_POLL);
+
+	mutex_unlock(&pipe->lock);
+
+	if (status & PIPE_POLL_IN)
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+	if (status & PIPE_POLL_OUT)
+		mask |= EPOLLOUT | EPOLLWRNORM;
+
+	if (status & PIPE_POLL_HUP)
+		mask |= EPOLLHUP;
+
+	if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+		mask |= EPOLLERR;
+
+	return mask;
+}
+
+static irqreturn_t goldfish_pipe_interrupt(int irq, void *dev_id)
+{
+	struct goldfish_pipe_dev *dev = dev_id;
+	unsigned long irq_flags;
+	int count = 0;
+
+	/*
+	 * We're going to read from the emulator a list of (channel,flags)
+	 * pairs corresponding to the wake events that occurred on each
+	 * blocked pipe (i.e. channel).
+	 */
+	spin_lock_irqsave(&dev->lock, irq_flags);
+	for (;;) {
+		/* First read the channel, 0 means the end of the list */
+		struct goldfish_pipe *pipe;
+		unsigned long wakes;
+		unsigned long channel = 0;
+
+#ifdef CONFIG_64BIT
+		channel =
+			(u64)readl(dev->base + PIPE_V1_REG_CHANNEL_HIGH) << 32;
+#endif
+		channel |= readl(dev->base + PIPE_V1_REG_CHANNEL);
+		if (!channel)
+			break;
+
+		/* Convert channel to struct pipe pointer + read wake flags */
+		wakes = readl(dev->base + PIPE_V1_REG_WAKES);
+		pipe  = (struct goldfish_pipe *)(ptrdiff_t)channel;
+
+		/* Did the emulator just closed a pipe? */
+		if (wakes & PIPE_WAKE_CLOSED) {
+			set_bit(BIT_CLOSED_ON_HOST, &pipe->flags);
+			wakes |= PIPE_WAKE_READ | PIPE_WAKE_WRITE;
+		}
+		if (wakes & PIPE_WAKE_READ)
+			clear_bit(BIT_WAKE_ON_READ, &pipe->flags);
+		if (wakes & PIPE_WAKE_WRITE)
+			clear_bit(BIT_WAKE_ON_WRITE, &pipe->flags);
+
+		wake_up_interruptible(&pipe->wake_queue);
+		count++;
+	}
+	spin_unlock_irqrestore(&dev->lock, irq_flags);
+
+	return (count == 0) ? IRQ_NONE : IRQ_HANDLED;
+}
+
+/* A helper function to get the instance of goldfish_pipe_dev from file */
+static struct goldfish_pipe_dev *to_goldfish_pipe_dev(struct file *file)
+{
+	struct miscdevice *miscdev = file->private_data;
+
+	return container_of(miscdev, struct goldfish_pipe_dev, miscdev);
+}
+
+/**
+ *	goldfish_pipe_open - open a channel to the AVD
+ *	@inode: inode of device
+ *	@file: file struct of opener
+ *
+ *	Create a new pipe link between the emulator and the use application.
+ *	Each new request produces a new pipe.
+ *
+ *	Note: we use the pipe ID as a mux. All goldfish emulations are 32bit
+ *	right now so this is fine. A move to 64bit will need this addressing
+ */
+static int goldfish_pipe_open(struct inode *inode, struct file *file)
+{
+	struct goldfish_pipe_dev *dev = to_goldfish_pipe_dev(file);
+	struct goldfish_pipe *pipe;
+	int status;
+
+	/* Allocate new pipe kernel object */
+	pipe = kzalloc(sizeof(*pipe), GFP_KERNEL);
+	if (!pipe)
+		return -ENOMEM;
+
+	pipe->dev = dev;
+	init_waitqueue_head(&pipe->wake_queue);
+	mutex_init(&pipe->lock);
+
+	/*
+	 * Now, tell the emulator we're opening a new pipe. We use the
+	 * pipe object's address as the channel identifier for simplicity.
+	 */
+
+	status = goldfish_cmd_status(pipe, PIPE_CMD_OPEN);
+	if (status < 0) {
+		kfree(pipe);
+		return status;
+	}
+
+	/* All is done, save the pipe into the file's private data field */
+	file->private_data = pipe;
+	return 0;
+}
+
+static int goldfish_pipe_release(struct inode *inode, struct file *filp)
+{
+	struct goldfish_pipe *pipe = filp->private_data;
+
+	pr_debug("%s: call. pipe=%p file=%p\n", __func__, pipe, filp);
+	/* The guest is closing the channel, so tell the emulator right now */
+	goldfish_cmd(pipe, PIPE_CMD_CLOSE);
+	kfree(pipe);
+	filp->private_data = NULL;
+	return 0;
+}
+
+static const struct file_operations goldfish_pipe_fops = {
+	.owner = THIS_MODULE,
+	.read = goldfish_pipe_read,
+	.write = goldfish_pipe_write,
+	.poll = goldfish_pipe_poll,
+	.open = goldfish_pipe_open,
+	.release = goldfish_pipe_release,
+};
+
+static void init_miscdevice(struct miscdevice *miscdev)
+{
+	memset(miscdev, 0, sizeof(*miscdev));
+
+	miscdev->minor = MISC_DYNAMIC_MINOR;
+	miscdev->name = DEVICE_NAME;
+	miscdev->fops = &goldfish_pipe_fops;
+};
+
+static int goldfish_pipe_device_deinit(void *raw_dev,
+				       struct platform_device *pdev);
+
+int goldfish_pipe_device_v1_init(struct platform_device *pdev,
+				 void __iomem *base,
+				 int irq)
+{
+	struct goldfish_pipe_dev *dev;
+	int err;
+
+	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->super.deinit = &goldfish_pipe_device_deinit;
+	dev->pdev_dev = &pdev->dev;
+	spin_lock_init(&dev->lock);
+
+	err = devm_request_irq(&pdev->dev, irq,
+			       &goldfish_pipe_interrupt, IRQF_SHARED,
+			       DEVICE_NAME, dev);
+	if (err) {
+		dev_err(&pdev->dev, "unable to allocate IRQ for v1\n");
+		return err;
+	}
+
+	init_miscdevice(&dev->miscdev);
+	err = misc_register(&dev->miscdev);
+	if (err) {
+		dev_err(&pdev->dev, "unable to register v1 device\n");
+		return err;
+	}
+
+	setup_access_params_addr(pdev, dev);
+
+	platform_set_drvdata(pdev, dev);
+	return 0;
+}
+
+static int goldfish_pipe_device_deinit(void *raw_dev,
+				       struct platform_device *pdev)
+{
+	struct goldfish_pipe_dev *dev = raw_dev;
+
+	misc_deregister(&dev->miscdev);
+	return 0;
+}
diff --git a/drivers/platform/goldfish/goldfish_pipe_v1.h b/drivers/platform/goldfish/goldfish_pipe_v1.h
new file mode 100644
index 000000000000..6d61441e2a7f
--- /dev/null
+++ b/drivers/platform/goldfish/goldfish_pipe_v1.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2018 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef GOLDFISH_PIPE_V1_H
+#define GOLDFISH_PIPE_V1_H
+
+/* The entry point to the pipe v1 driver */
+int goldfish_pipe_device_v1_init(struct platform_device *pdev,
+				 void __iomem *base,
+				 int irq);
+
+#endif /* #define GOLDFISH_PIPE_V1_H */
-- 
2.19.0.605.g01d371f741-goog

Re: [PATCH v2 06/21] platform: goldfish: pipe: Add DMA support to goldfish pipe

[Greg KH]

On Wed, Sep 26, 2018 at 04:02:19PM -0700, rkir@google.com wrote:
> From: Roman Kiryanov <rkir@google.com>
> 
> Goldfish DMA is an extension to the pipe device and is designed
> to facilitate high-speed RAM->RAM transfers from guest to host.
> 
> See uapi/linux/goldfish/goldfish_dma.h for more details.
> 
> Signed-off-by: Roman Kiryanov <rkir@google.com>
> Signed-off-by: Lingfeng Yang <lfy@google.com>
> ---
> Changes in v2:
>  - Got sign-off from Lingfeng Yang.
>  - Removed the license boilerplate from goldfish_dma.h.
>  - Rebased.

I don't understand this series.  Please start over with 01/XX as your
other patches were all merged.

And I still think you need a better justification for this, given the
many other ways the kernel already has for this feature...

thanks,

greg k-h